I started thinking about board sizes V speed + liveliness yesterday.. Ok my 125ltre board was my mothership + 60 over my weight so it wasn't very lively or fast compared to my 78ltre ( +13)..
I suppose a lot of factors come into it the 125 was a freeride the 78 a waveboard but I'm assuming a lot has to do with the wind strength and sail size you use..?
So assuming the sailors are the same level , fitness etc using the same style of board but just different sizes would the amount over their weight be the main factor that would affect the feel?
Like my little board whips around the gybes and I have trouble keeping up with it whereas my 95 ltre is much easier to stay with ( some of that would be freeride V wave + sea state).
I suppose what I was musing over was a 125 feels like a tank to me and slow whereas i suppose to someone 100kgs it would feel and be faster? 160ltre board would be their equivalent to my 125..
Sorry I'm bored..

It would depend on local conditions a bit. Ocean waves tend to smooth the water a bit.

Big board becomes bouncy and you have to carve wide turns.
Medium board should be comfortable over a wide wind range and until the water gets choppy from the wind.
Small board is nice if you get steady strong winds but the problem is usually the stop/start nature of strong winds.

I prefer my big board to just be big enough to uphaul. 6.5m to 4.5m
Medium board to suit the best conditions. 5.7m to 4m
Small board for when its too windy for the medium board (below 4m weather unless the wind is consistent), so it doesn't get much use. 5m to 3.7m but could go to 3.3m.

I'm thinking of changing my medium board to one with a slightly larger wind range and going down to two boards

This has got me thinking there must be a stage where the sail gets too small to have mast enough foot pressure for a given board size so then they would bounce more? So would a lightweight whose using a 80ltre board with a 3.2m find it bouncier than a heavier person using it in the same conditions with a 5m?
I need to get down to some work..